Method of and apparatus for spreading folded signature leaves



United States Patent Inventor Rudolf Hepp Schmidt-Ott-Strasse 721, Berlin 41, Germany App], No. 690,445 Filed Dec- 14, 1967 Patented Dec. 15, 1970 Priority May 10, 1967 Germany No. 1162691 METHOD OF AND APPARATUS FOR SPREADING FGLDED SIGNATURE LEAVES 4 Claims, 9 Drawing Figs.

US. Cl. 270/54 Int. Cl B65h 39/02 Field of Search 270/54 [56] References Cited UNITED STATES PATENTS 2,791,421 5/1957 Schramm 270/54 3,087,721 4/1963 McCain.. 270/54 3,176,976 4/1965 Hepp 270/54 Primary ExaminerLawrence Charles Att0rney- Karl F. Ross ABSTRACT: A signature folded with an overhanging edge is fed, overhang first, between a pair of spreading rollers provided with gripping hooks which are spaced apart sufficiently to let the shorter leaf pass while the longer leaf is engaged by the hook of the roller proximal to it. Depending on the position of the overhang, the sheet-feeding mechanism is swung to one side or the other to move its longer leaf closer to the respective roller while aligning the shorter leaf with the gap between the hooks. The rollers also carry suction heads to separate the leaves of symmetrically folded signatures.

PATENTED nan 5 i976 sum 1 u? 3 Fig. 2

IIIIIIIITTTQ'T'I' iiud 01f IIEPP In wen [or PATENTEU UEC] 5197B SHEET 2 UP 3 In men for PATENTED DEC] 5 I970 SHEET 3 UF 3 Bud olf uEpp METHOD OF AND APPARATUS FOR SPREADING FOLDED SIGNATURE LEAVES My present invention relates to a method of spreading folded sheets, known as signatures, and to an apparatus for carrying out that method. I t

In my prior US. Pat. No. 3,176,976 I have disclosed a method and an apparatus of this type wherein a rotating drum is used to remove successive signatures'from-the bottom of a stack in which these signatures, each folded with a longer and a shorter leaf so as to form an overhanging edge, are so placed that their overhanging edges are positioned on the same side of the stack and on the upper leaf of each signature. Upon removal of a signature from the stack, this overhanging edge is engaged by a gripper in the form of a roller with a radially projecting hook which separates the longer leaf from the associated shorter leaf as the latter is gripped by a similar hook of a second roller. This system operates only on signatures having their overhanging edges on a predetermined side of the transport path along which they are fed toward the spreading rollers.

In the manufacture of brochures, book blocks and the like it is frequently necessary to assemble signatures whose overhanging edges are on opposite sides. Thus, the general object of my present invention is to provide a method of and an apparatus for spreading, in a simple manner and without interruption of feed, a succession of signatures having their overhanging edges partly on one and partly on the other side of their transport path.

A more specific object is to provide a device which can also operate on symmetrically folded signatures, i.e. on sheets without overhang.

In accordance with my present invention, I provide a pair of transversely spaced symmetrical grippers, advantageously of the cylindrical type with radially projecting hooks, which are positioned on opposite sides of the transport path for the signatures with sufficient spacing to give clearance to a leaf passing midway between these grippers. A signature advancing toward the gap between these grippers, having an overhanging edge at one or the other side of the transport path, is so guided that its longer leaf passes close to the gripper on the side of the overhanging edge while its shorter lead advances substantially midway through the gap so as not to be engaged by either gripper.

With roller-type grippers, according to a more specific feature of my invention, the feed mechanism advancing the signatures toward the rollers is so controlled as to guide the longer leaf of each signature along a line substantially tangent to the proximal roller to insure the engagement of its leading edge by the corresponding gripping hook. Advantageously, this feed mechanism comprises a conveyor belt mounted, together with counterpressure means such as a pair of nondriven rollers, on a support which is swingable through a limited angle to impart the desired orientation to the signatures advanced thereby. The control means for shifting the position of the feeder may comprise an electromagnetic actuator such as a solenoid working against a restoring spring. The actuator may in turn be controlled by a counter, or by a pair of counters, establishing a predetermined rhythm for the alternation of the feeder between its two operating positions. Thus, one counter may determine the number of operating cycles for the processing of a series of signatures with right-hand overhang whereas the other counter determines the number of consecutive cycles during which signatures with left-hand overhang are to be spread out. By virtue of their symmetrical position, the two spreading rollers may also be provided with suction heads adapted to separate the leaves of symmetrically folded signatures passing therebetween.

The invention will now be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a perspective view of folded sheet or signature with projecting front leaf;

FIG. 2 is a perspective view of a folded sheet with projecting rear leaf;

FIG. 3 shows a symmetrically folded signature;

FIG. 4 is a diagrammatical representation of a device embodying the invention;

FIG. 5 is a side view, partly in section, of the device of FIG. 4 operating on a signature with right-hand overhang as in FIG. 1;

FIG. 6 is a view of the lower part of FIG. 5 in an advanced stage of operation;

FIGS. 7 and 8 are views similar to FIG. 6, showing the device in the stages of operation of FIGS. 5 and 6 with a signature of the type illustrated in FIG. 2, i.e. with left-hand overhang; and

FIG. 9 is a view similar to FIGS. 6--8, showing the device operating on symmetrically folded sheets.

FIG. I. shows a signature 1A having a projecting edge or overhang 211 on its front or right-hand side, opposite its fold ridge or back 3. FIG. 2 shows a signature 18 with a projecting edge 2b on its rear or left-hand side. FIG. 3 shows a symmetrically folded sheet 1C which has a centrally positioned fold ridge 3 and coextensive sides 5 without overhang.

FIG. 4 shows a device 6, embodying my invention, onto which is placed a stack 9 of folded sheets generally designated 1. The individual sheets of the stack 9 are guided along bars 8. A transport chain 7, moving in the direction of the arrow A underneath the device 6, is straddled by the sheets I discharged by that device in spread-out form.

As best seen in FIG. 5, the device 6 comprises a drum 10 for the removal of successive signatures from the stack 9.

The individual sheets of the stack 9 abut with their backs 3 against the guide rails 8, so that their edges with the overhang 2 are located at the left side of the stack 9. The drum 10 rotates counterclockwise about its central axis as shown by the arrow B. Three gripper rollers 11 journaled in the drum 10 rotate clockwise as shown by arrows, i.e. contrary to the direction of rotation of the drum itself. The gripper rollers 11 are each equipped with a suction head 12. When the drum 10 is in the position shown in FIG. 5, the suction head 12 of the right-hand gripper roller 11 has engaged the bottom sheet of the stack 9 near its fold ridge 3; on further counterclockwise movement of the drum l0 and simultaneous clockwise rotation of the gripper rollers, the sheet is wound up on the roller 1 1 by which it is engaged.

When this gripper roller 11 reaches the left-hand position 5, its suction head 12 frees the engaged sheet which at this point is gripped and firmly held by a detent 14. On further movement of the drum 10, the sheet is unwound from the gripper roller 11 and places itself against a brush 15. Upon continuing rotation, a set of guide rollers 13 also rotatable in the clockwise direction come into contact with the unwound sheet. When the gripper hook 16, positioned in FIG. 5 underneath the stack 9, reaches the vicinity of the detent 14, the

latter releases the sheet resting on the brush 15; as shown at the left of FIG. 5, the gripper hook 16 reaches behind the fold ridge of the sheet and ejects it from the drum with its overhanging edge leading, so that the sheet comes into engagement with a feeder 17 which comprises a driven conveyor belt 18 and two pressure rollers 19 bearing thereon. A bellcrank lever with arms 20, 21 is fixed to the end of the feeder I7 proximal to the drum 10 so that this lever is swingable together with the feeder about a pivotal axis 22. A contractile spring 23 is anchored to the free end of the lever arm 20 to urge the feeder 17 into the position shown in FIG. 5. A rod 24 is attached to the free end of the lever arm 21, its other end being articulated to lever 25 which is pivotable about an axis 26.

The free end of lever 25 is articulated to a magnetic core 27 of a solenoid 28 whose energization moves this lever 25 and with it the feeder 17 into an alternate position shown in FIG. 7. Underneath thefeeder 17 there are symmetrically mounted two roller-shaped spreading tools 29, 30 having radially projecting gripper hooks 31, 32 and, in addition, suction heads 33, 34. It will be noted that the hooks 31, 32 are separated by a gap large enough to clear one leaf of a folded signature passing between the rollers 29, 30.

The device of the invention functions as follows; when the sheet ejected from the drum 10 passes the feeder 17 as shown in FIG. 6, the overhang 2a on its right-hand side comes into engagement with the gripper hook 31 of the spreading roller 29 as the longer leaf of the sheet moves on a path substantially tangent to the roller. On further rotation of the two spreading rollers, the overhang gripped by the hook 21 is separated from the opposite sheet side which thereupon passes between the rollers 29, 30 without engagement by their hooks, so that, on release of the overhanging sheet edge by the gripping hook 31,

the two leaves of the signature straddle the transporting chain 7. In FIGS. 5 and 6 the feeder 17 has been swung to the right (arrow. D) so that signatures 1A of the type shown in FIG. I can be spread.

When signatures 18 with left-hand overhang 2b, as shown in FIG. 2, are to be processed, the solenoid 28 is energized so that the lever 25 and with it the feeder 17 are shifted into their alternate position (arrow E) in accordance with FIGS. 7 and 8 whereby the longer (left-hand) leaf of the signature advances on a path substantially tangent to roller 30. When, as shown in FIG. 7, the overhang 2b comes into engagement with the gripper hook 32 of the spreading roller 30, so that, as shown in FIG. 8, the sheet is opened and placedon the transporting chain 7. Thus, the actuation of the solenoid 28 alters the attitude of the sheet passing the feeder 17 to direct its overhang .to the proximal spreading roller. If again sheets with righthand overhang 2a are to be processed, the solenoid 28 is deenergized whereupon the spring 23 restores the feeder l7 and with it also the lever 25 to the position of FIG. 5 in which the sheet-engaging run of belt 18 is inclined to the right of the line of symmetry bisecting the gap between the rollers 29, 30.

FIG. 9 shows the spreading of a symmetrically folded sheet of the type illustrated in FIG. 3. When such a sheet passes between the spreading rollers 29, 30, the gripper hooks 31, 32 are not actuated. Instead, the suction heads 33, 34 are switched on to grip the two sides of the sheet and open it up so that the sheet, on release by these suction heads, alights on the transporting chain 7.

In FIG. 9 the position of feeder l7 and its actuating mechanism 24-28 corresponds to that of FIGS. 5 and 6 although it will be apparent that this is not essential for the separation of the signature halves by means of suction heads The attitude of the feeder 17 may' be controlled by a counter, diagrammatically indicated at 35 in FIG. 5, which determines the number of operating cycles during which the solenoid 28 is to be maintained in either of its two states of operation, in conformity with the number of signatures with right-hand and left-hand overhang assembled in the stack 9.

Iclaim: v

I. An apparatus for spreading a succession of signatures each folded with a shorter and a longer leaf to form an overhanging edge, comprising feed means for advancing successive signatures along a transport path with their overhanging edges partly on one and partly on the other side of said path, a pair of grippers symmetrically disposed on opposite sides of said path with sufiicient spacing to. give clearance to a leaf passing midway between said grippers, and control means for said feed means selectively operable to shift each signature approaching said grippers into a position in which said longer leaf passes close to the proximal gripper for engagement thereby while said shorter leaf advances substantially midway between said grippers, said grippers comprising -a pair of counterrotating rollers with radially projecting hooks, said feed means comprising mechanism positionable by said control means to guide said longer leaf on a line substantially tangent to the roller proximal thereto, a conveyor belt having a sheetengaging-run trained upon the gap between said rollers, and counterpressure means for holding a signature in contact with said run, said belt and said counterpressure means pivotally mounted for limited swinging by said control means.

2. An apparatus as defined in claim 1, further comprising counter means coupled with said control means for shifting said feed means in a predetermined rhythm between respective operating positions for signatures having their overhanging edges on opposite sides.

3. An apparatus as defined in claim '1 wherein said rollers are further provided'with suction means for simultaneously engaging the leaves of symmetrically folded signatures passing therebetween.

4. An apparatus as defined in claim 1 wherein said control means comprises an electromagnetic actuator and a restoring spring anchored to the mounting of said belt and said counterpressure means. 

